“Any food-related item could potentially be a source of contamination, but as the coffee is brewed or boiled, this is less likely to be a common source of infection transmission. In any event, these items should be regularly cleaned as per the manufacturer’s recommendations,” Dr Glatt said.

It’s the “regular cleaning part” that’s the issue here. In order to prevent mould and bacteria from growing inside of coffee makers, they need to be cleaned every few months with vinegar. Hot water alone won’t kill the mould, so don’t think a quick rinse in the sink will cleanse your communal coffee maker.

But how often do you think hotels are doing this to in-room coffee makers?

A study by the University of Valencia tested nine different Nespresso machines that had been in use for at least one year. The report states: “All the machines revealed a significant bacterial diversity, with the total number of identified genera ranging from 35 to 67,” meaning a “moderately to highly abundant” quantity.

And it’s not just the inside of the hotel room coffee maker that you have to worry about.

“An interesting thing about germs in hotel rooms is that they aren’t solely due to the people staying in those rooms,” Dr Charles Gerba, professor of microbiology and environmental sciences at the University of Arizona, warns.

“In fact, we’ve done virus tracer studies where we found that maids move the viruses from room to room during cleaning.”